I have bought many many road-ish tires for 26 in rims over the years... anything from proper slicks to treaded... lately my faves are Intense Micro Knobbies (the folding ones; they have wire ones as well - don't bother, they are rubbish)... this is what they look like:
They come in 2.1 or 2.25... I've used both. They look so radical, that they are "BADical"...
Currently I have the 2.25's on my uhhh... "carbon everything, full suss, single-speed, drop bar, franken-bike"?
I use this bike to ride on/in all manner of surfaces, places, trails, etc when I am in the mood for just a bit of fun! :roll:
The tires have extremely low rolling resistance... it's actually a dirt jump tire; on the road you can hardly feel them at all... but anywhere else they five juuuuust the right amount of grip. I use them all over the place. On this particular bike, they've been thrashed. Haven't had a puncture yet!