1) Pilot: It sets things up very well--maybe too well; the shot-on-film first episode is way better than much of what follows it.
2) All You Need Is Love: Looks at that great 1980s fad--video dating services--and features fun guest stars like Rita Wilson and Stepfanie Kramer. More importantly, it's funny; the reveal involving Wilson's character is great.
3) Who's on Thirst: I believe this is one of the more well-known episodes of the show, and I can say that rewatching it for the podcast, I remembered some of the specific gags 35-40 years later. (I may have first seen it in a rerun). Kip and Henry get stranded in a cabin and become increasingly desperate.
4) The Way Kip and Henry Were: I really enjoy this look at how the lads got a job with Ruth right after (Well, not quite, as we learn) graduating college. It ends on a poignant moment that actually works.
5) The Rewrite: This is one of the first-season episodes that gets at the potential of the show--a little unhinged and goofy, sometimes even surreal, but saying something about the characters.
And 5 other episodes to check out to get a feel for the series:
1) Gotta Dance: It features several things I generally dislike when the show features them: singing/dancing, fake commercials--but it does it much better than many other episodes and features some insight into Kip's relationship with Sunny.
2) There's No Business: This explains how the guys create their 60 Seconds Street agency (though it doesn't go into detail on that sign) with a slimy turn by Joe Regalbuto.
3) The Two Percent Solution: Bringing in Ruth as a silent partner (see the previous entry) was a little flimsy, but this episode looks at the dynamic of the trio (plus Amy, who has the titular interest) as business partners. It's an interesting approach.
4) The Road to Monte Carlo: A life-changing incident, kind of a funny accident, really, makes Kip and Henry re-evaluate their lives.
5) The Truth and Other Lies: Here's where the show, for all intents and purposes, ditches the central cross-dressing gimmick and has the guys come clean.