I've found myself playing my sims this way, and decided that it deserved to be called a "challenge" for some people. Although it may seem contradictory, I've composed some "rules" to this challenge, and the difficult part may be getting anything out of it. Oh well, I think it's all groovy:
1 Playable sims must be made in CAS.
2 Sims must have bad hair and ugly clothes.
3 Sims must have hippie-style names (like "Windy Moonbeam" or "Forrest Treeshine").
4 Sims must have the following approved personality: Active < 4 and Nice > 6. This means that only the following signs are possible: Cancer, Virgo, Libra, Capricorn, Aquarius, and Pisces (the archetype for hippie Pisces is 5, 4, 3, 3, 10).
5 Sims are not permitted to go to work (i.e. finding a job is okay, so long as they don't actually go to work).
6 You must play at all times with "aging off" cheat (except at Uni).
7 Sims who attend school must maintain C or lower grade, and Uni sims must drop out before their third year.
8 All other grooviness is encouraged and being square is totally uncool.
There's no scoring or goal-reaching, because those things are all part of the evil corporate "system" that are designed to keep you down and be uncool.