Wait a minute!
See, Andromeda is coming soon, at a co-ordinate near you!
http://en.wikipedia.org/wiki/Androme..._Way_collision
No seriously though,
MAPNUT, there are a few threads here, which have delved into this area.
In fact I filed (so safely, i don't know where) a link, from one of the posts on a particular thread, recently, which has a computer generated sequence of such phenomenal cosmic events. I can't for the life of me, remember who provided that link.
You could do BAUT search to take you there. I'll try locate it for you, unless some one kinder and faster, here, beats me to it. I wouldn't be surprised.