Smash Lab was OK last season but I haven't been impressed this year.
How It's Made is fine when you don't need fine-grained detail; it's fine to leave on in the background.
Cash Cab is probably the most easy to watch game show around and is a goods trivia mix.
Unfortunately, I'm a little bored with most of the rest of the Discovery Channel family lineup.
Current regular TV shows I'm enjoying are
Burn Notice (good for
Bruce Campbell fans) and the David Tenant
Dr. Who. Dr. Who just wrapped, though, and they won't be doing anything but some specials until 2010, but SciFi will certainly keep it going in reruns. PBS' airings are better than SciFi's though, as PBS has the whole hour to fill and uses the extra time to show the extras/'making of' from each episode if there are any.
I'm waiting for
Chuck to resume, and to a lesser extent
Heroes &
Life.