I watch Marseille whenever I can, which usually means tuning in about 4 hours on Channel 4, if they're showing a Marseille match. The atmosphere in the Stade Velodrome is absolutely amazing.
That said I will watch any football match if its on telly, but seeing as I only have terrestrial in my room (with no Channel 5), that's rather limited! However, during any Euro/WC tournament, I tend to watch every single game (apart from the rare occasions where I have to do something else), even throughout the first stage with the crappy matches.
Edit: they've moved it forward to about 1am now which is pretty nifty: PSG - Bordeaux tonight. Not too bad a game to watch, Pauleta got a hattrick and they won 3-1. Shame they're not showing Marseille, they won 3-1 as well away at Nantes on Saturday.