Battlestar Galactica 
2x11 Resurrection Ship Part 1
2x12 Resurrection Ship Part 2
Holy frak. I'm beginning to really see where all the plaudits come from -- BSG was pretty great before, but these mid-season episodes are really pushing it to another level.
The only thing standing between these being listed right after Pegasus was midnight -- a pair of gripping cliffhangers easily ensured my undivided attention for the full two-and-a-half hours of these three episodes back to back.
Mock the Week
9x02 (24/6/10 edition)
It comes to something when Jack Whitehall is your most famous guest. Not necessarily a problem, but it really does come to something when he's also the funniest. (See also: Graham Norton a few weeks back.)
Relatedly -- that white South African guy's act seemed to consist wholly of impersonating black South Africans in a rather awkward, arguably racist fashion. Uncomfortable. And not in the good Frankie Boyle-ish way.
[Watch it (again) on iPlayer.]