In all seriousness, don't forget to get your hair cut, especially if you're a guy. Otherwise, you might start looking like a hippie over the next few weeks, and no one wants that.
On the second night of Pesach, we start counting the Omer. During this 50 day period, it's customary not to get a haircut. Different groups measure the custom differently, but they all agree that it counts between now and Lag B'Omer. (To my knowledge, if there is a correction in the comments, I'll update this.) That's a little over a month. Most of you can live without a haircut for a month if you have to, but why put yourself through the inconvenience? It's also nice to go into chag feeling so fresh and so clean-clean. In fact, it's a mitzvah to get cleaned up before a chag! Haircut, new clothes, do something special for yourself as a way of bringing honor to the holiday. (But don't use that as an excuse to justify bad financial decisions.)
The men: According to custom, no getting haircuts and no shaving during the Omer (well, the applicable period of the Omer, according to your custom or community). That's not absolute, but it's a strong custom. Many men do shave during this time for either professional or "shalom bayis" reasons. I have found these "excuses" (heters, to be more precise) to be relatively common among the normally-clean-shaven modern orthodox. Many wives hate beards in our society, and they can create a real shalom bayis issue. Shalom bayis is far more important than this custom, so custom yields. The question many ask (usually men) is whether a wife should just accept the importance of this custom and "suck it up," so to speak. That may be the practice in some communities, whether they say so or not. For whatever reason, the rabbis have pretty consistently held that we womenfolk are not required to "suck it up." Why? We want you guys doing things that create babies, and that's unlikely when the woman is grossed out. #Fact. That seems to be the reasoning, from my perspective anyway.
Interestingly, I have seen men cite shalom bayis when in reality, their wives don't care either way. (This brings up the excellent question of why someone would ask another why he is clean-shaven, which seems like a very rude question to ask in the first place. Best case scenario: you get a answer that shows why it's halachically allowed. Worst case: you embarrass the man and "out" him as someone violating halacha/custom/practice, and what gives you that right?) These men just don't want the itchiness, feel self-conscious, or any other number of reasons for not wanting to have a beard. Whether that's right or wrong is not the discussion; I'm just sharing what real people are doing in real life.
As a whole, more men are growing beards during the Omer because Lumberjack Chic has become popular and professionally acceptable. However, that is only if the man can grow a beard in an "attractive" way, according to our society's style. Those who are patchy or scraggly or will grow a long beard very fast may encounter more resistance from a professional job standpoint. Of course, if you work with food, you will have a different set of considerations and regulations to deal with if you choose to not shave. If that's the case, sit down with your boss before you start growing the beard. It may be just as problematic for your boss as you. For instance, if she or he needs to order beard hairnets (yes, those exist!).
Can you clean up the beard or trim it? I don't know the answer to that question, but my guess is no, since haircuts are also verboten. This is why men with Lumberjack-worthy testosterone levels may run into problems in the office. No one wants to play "co-worker or hobo?" Many workplaces have a written policy with beard-grooming standards, so check your beard before you wreck your beard.
What about the women? Most women follow the custom to not get haircuts just the same as men do. The question is whether women have actively chosen to take on this minhag or whether women believe (mistakenly, according to nearly everyone if not everyone) it is obligatory on both sexes. If you're female and you have this custom, I have seen at least one tshuva (written ruling) that said that married women should get a haircut during this time if it affects (or will affect) their haircovering. For example, if your hair will get too long and be unwieldy under your haircovering choice (wig, hat, whatever), then you should get a haircut regardless of custom. From what I remember, the threshold for discomfort was very broad and inclusive, perhaps as low as an inconvenience. The mitzvah of haircovering trumps the custom, according to this teshuva. Whether haircovering is a mitzvah (and if so, what the parameters are) is a different discussion, but this position allows a haircut even for haircovering women who hold it is obligatory. (In fact, the argument is less strong if you believe haircovering is not a mitzvah or is a mitzvah that is not mandatory today - then it's custom v. custom, and which trumps the other?)
What about non-head hair? Women can definitely shave/trim/wax any non-head hair during the Omer. Yes, any. I don't know a definitive answer for men, but I believe the customary restrictions only apply to the head. What you do with the hair on the rest of your body is between you, Hashem, and possibly your wife. So if you're Michael Phelps, you're probably a-ok, especially since then swimming would be your profession. As you saw above, parnasah matters when making these rulings that affect your personal appearance.
So pick up your phone and call your hairdresser for an appointment right now, before you forget.