We did something recently here at Epsilon Gamma that went well: we hosted a Date Night. All of our members brought a date, and we all went bowling and out to eat. This is great because not only does it make a great social function, but helps to get our letters out there (my date had never heard of SAI).
PMA here hosts Monday Night Football Parties every Monday night at Wings To Go, and SAIs are always invited. This is always a lot of fun; we rarely actually watch the game...we just hang out.
Hope this helps!