BBC 2 just started airing a new quiz show called Beat the Brain. It has mental challenges similar to those that were on Krypton Factor, but pretty much all of them are easy to play along with at home. Here's a full episode on Youtube:
https://www.youtube.com/watch?v=5nS-VB0L1LYAlso, one thing in particular I like about this show is that the team has a very good shot of leaving with a half-decent amount of money, unlike most BBC quiz shows where either you're playing for pride and a trophy if you end up being the grand champion (Only Connect, Mastermind, University Challenge, etc.) or you're playing for a £1,000 roll-over jackpot that is usually quite difficult to win so that it usually rolls over to a decent amount before it is won (Pointless, Two Tribes, Eggheads, Perfection, etc.).