Since everyone is doing it, I think I will suggest some too. ^^
Personally I think "Wann wird's mal wieder richtig Sommer" by Rudi Carrell would be really fitting around this time of the year, though we already have really warm weather. XD
I also would love to take some Ärzte Songs, but I fear they might be a bit too advanced, since some of that stuff uses words even a normal German doesn't use in day to day language. And some stuff has so much Ironie (Friedenspanzer) that it is a little hard to get across, but maybe you can take "Schrei nach Liebe" or "Hurra", which might be a little hard to understand without the cultural context but could work as a stand alone.
And with Chucks liking for "Rammstein" you really should take one of those. ^^
My personal favorit is "Spieluhr", but that might be way to complex. So why not "Sonne" or something like that? ^^
Oh, and since I think that we have some Tote Hosen fans here:
why not something by them too? "Eisgekühlter Bomolunder" might be to silly, but how about "Bonnie and Clyde" or "Bayern München"? The later would be a good frame for some soccer comments. ;P
And personally I like the stuff by Horch or Lacrimosa. Subway to Sally also made some really good songs, only I would be careful with the controversial or the christian stuff they did...
That be all from me for now. ^^'
Maybe someone else can give some suggestions for these bands too. ^_^;;