Kelvingrove Transport Museum is great! I second that, then you could head up to Ashton Lane which has some nice food and pubs and is quite old and unique looking little street - there is a cinema as well where you don't buy a seat, you get a sofa and can get drinks and food as well, also has the Stand comedy club nearby. You can get the underground from the West End to town as well.
Buchanan Street for shopping if the missus fancies. Argyle street and Sauchiehall street have shops too and are at the top and bottom of Buchanan Street.
Always worth checking out King Tuts or the ABC or Carling Academy to see if anyone good is on and there are tickets? Don't know if you are into your DJs or anything? Usually good for that in Glasgow too! If any of that interests you, ask me and I can point out more places etc.
There is the GFT cinema, Imax.
There are a billion places to eat out! I wouldn't know where to start with recommendations, renowned for a good Indian curry though!
Do you have transport? You can get out of Glasgow to the coast down Ayrshire in next to no time. Or Langbank. Or X-Scape! For a bit of climbing, snowboarding.
For some Celtic stuff, Bairds bar in the Gallowgate/Barrowlands has lots of memorabilia and stuff in it which is nice to look around, it's real old-school pubs and will have some characters! Don't use the toilets and don't buy draught

I also wouldn't go after the game or later in the evening!
Okay that oughta do for now? Feel free to ask if I've missed anything! It's a great city and there is no doubt plenty I have forgotten!