I know this is related to University Life. I think I know what causes the everyday party invites at Sims University. Befriending a Sim in University will trigger it and it can occur with any Sim whatever the Sim is from Frat, Sorority or even the Professor, that Sim will invite you to a party everyday usually on 2:30 PM. This was reported in the University Life bug thread.
I tested this with a Sim who wasn't friends with anyone at Sims University and I did not get a party invite at 2:30 PM.
Also the click bug where you can't click on Sims doesn't happen on newer saves.