Some variations of the legacy challenge - Uglacy (try to breed uglier Sims over time), Prettacy (start with an ugly Sims and try to make prettier), Perfect Genetics (maintain a unique hair and eye colour combination through the generations), Alphabetacy - each generation of children have names starting with a certain letter of the alphabet (children of the founders start with A, their children start with B )
Please note, if you are creating a challenge, you need to post it on a blog or in the forums. I will not link to challenges in profiles and I prefer not to link to them if they are embedded in YouTube. The forums and most blogs allow discussions which is friendlier.
If you are new, you can still post the url. You just can't link to it directly. So just type or paste in "www.mysimsblog.com/thispost" or "forums.thesims.com/en_US/post/788042" in your reply. It's far easier to correctly find the right location that way.
The Bachelor/Bachelorette Challenge isn't really a challenge in the sense that everything on the lists above are. It's a personality compatibility test to find a spouse for a Sim. Because of the nature of the contest, the rules are usually changed a lot to suit the player and the Sim looking for a mate. That said, apparently everyone expects it to be on the list. So it's here.