Looking back, most of my major developments in terms of quality and skill were thanks to the pressure and motivation of contests, and most of my failures were because they lacked that. I think they really help bring us together, and push us all to our limits. I've entered seven animation challenges, and those are great, but I've yet to enter BRAWL. (Hint, hint)
I've got TOY, two THACs, seven animation challenges, OYO, the Tongal thing, the Santa Yoda thing, the Lego Superheroes thing, and EASTER under my belt, and you know what, those were some great times.
Long, more involved contests are a bit hard to commit to, especially now with work and then college looming on the horizon, but short time-frame stuff like THAC, BRAWL, EASTER and the challenges are and were great fun, and attract quite a couple participants. (Well, the bigger BiM-Endorsed ones do.)
Speaking of which, has anybody come forward about BRAWL yet? It's normally held what, a month and a half from now? If somebody is going to do it, they'd better start thinking about it soon.
Having done EASTER, I'd like to say that hosting a contest really isn't that hard. Yeah, I slipped out on prizes, but the rest is easy. If anybody out there is thinking about hosting something, please, please consider doing it.
TOY was what got me to finally join this site and get involved. And who knows how many others joined because of cool contests. And third-party contests do get participants, just look at Spider's Christmas in a Minute, and didn't ZachFB get quite a few in his?
So yeah, don't be afraid to come out and host something. It's fun, and really helps the community.