jabber transport would be a solution to the aim problem. vpning to another site would be another solution (hamachi does this in a sense). Neither solution will help you out with css (1 won't work, and 1 will cause the game to be very slow)
Not to be the rain on the parade but if the Uni feels that these ports are causing a problem on THEIR network, then we should not be providing work arounds.
Maybe go talk to a sys admin and be up front. Might be able to get atleast AIM. As for networking gaming, fat chance, but be up front and see if the people in charge of the network will provide you with the resources you need.