One thing about the student body government elections are that they are essentially rigged. There's always a frat guy who becomes president, because all of the fraternities and sororities put their efforts into having a certain frat guy become president, and as a result, the majority of student activity funding goes to frats. I would imagine this happens at other schools as well but it doesn't make it acceptable. I guess that would be good if that was more your kind of crowd. But it makes it a bit unfair because other campus clubs have to resort to fundraisers for funding.
One thing that stands out about UCI campus clubs is that there are what feels like hundreds of Christian clubs. In the OC, Christianity seems to be pretty big, especially for Asians. (By the way, I'm Asian myself). But it is sort of nonsensical in that many of these Christian clubs are just excuses for partaking in social activities with the false illusion of "being religious". If you get lulled into the on-campus Christian club bubble (a bubble in itself, inside another bubble, the OC bubble), you'll miss out on a lot of things that university life offers, and you'll lose precious time in building up your credentials to land a job after college. I don't want this to sound like an anti-Christian rant -- if you want to become more Christian or what not, it's better to spend more time at your church than to waste it with the on-campus Christian clubs, because there's nothing too religious about them.
On-campus throughout the week there are many events that happen, whether they be in beautiful Aldrich Park or in the nice newly renovated Student Center. There is a good selection of interesting events, guest speakers, plays, movie prescreenings, athletic events, etc. that happen on campus. There's not really a shortage of things to do. The problem is that most students who are not freshmen live off-campus, sometimes a good distance from campus. Many people of those off-campus people do their own thing.
If you're looking for parties, get involved with fraternities/sororities. That's pretty much the best way to get in on that.
Things to do in Irvine are pretty much just eating out, shopping, and going to the movies. Most of the wilder/more interesting things are outside of Irvine. Fortunately Irvine isn't that big, so going outside of Irvine won't take much time (15 minutes by car).