I travel to Philly quite a bit. Here a list of things to do in order:
1) Go to Geno's or Pat's, neither is as cool as the Varsity; but it is something to do.
2) Go tour the battleship New Jersey, it is in New Jersey of course; but it is close by.
3) Go tour the US Mint.
4) Go see a bell with a crack in it.
5) Go eat at Ralph's or Romano's. Philly has lots of good Italian food and these two places have claims to fame (sort of).
6) Go to a museum.
I think that about sums it up. Feel free to add to this list if you like.