Ok well since I am bored I will try to cover some of the events that greeks have at my school every year.
ADPi - 8 Ball (pool tournament)
Alpha Phi - Aphifa is what I think it's called...(soccer), HayPhiver (hayride)
AXO - Greeks on the Gridiron which is football, right Jules?
DG - Anchor Splash, Pinafore
Tri Delt - I should know this b/c there is not one fraternity guy on our campus who doesn't have one of their philanthropy t-shirts...well I forget the name, but it's a hugely popular baseball tournament
Theta - I actually have no clue, that's really bad oops
KD - Flamingo Flock or something along those lines, it's a date party
Gamma Phi - Used to do Moonbowl which was bowling, they also do a party with SAE every year called Goldfish
ZTA - Another one where I have no idea, oops
Phi Mu - Miracle Man (male beauty pageant)
Kappa - Also no idea what their philanthropy is, they also do Monmouth with Pi Phi (hayride/semiformal)
Pi Phi - BMOC which is basketball, Monmouth
Chi O - Serena Di Luna which is their formal I think or semiformal
Also I think that Theta, DG, and Kappa do Kite, Key, and Anchor
As for the fraternities there are so many that I am not going to list them all but some of the events they have are Beta's Pig Roast and Wooglin Night Club (semiformal in Chicago), Pike Stock, Delt does Mekong Delta which is an overnight campout date party thing, Fiji of course has Fiji Island, Sigma Nu does Snakes on the Lake (semiformal), and yeah that's all I can think of. There are about 15 more fraternities though I just can't think of anything at the moment, but I know they all pretty much have annual events.