Pearl Izumi and Zoic make bike shorts that look like any casual shorts -- no weird looking strips of spandex or lycra (although some of their other shorts do have those). I put a few on my Amazon wish list and waited until they went on sale. A couple of months ago Amazon had a brief sale on the Pearl Izumi plaid canyon shorts at $20, way down from the usual price. Great shorts, wish I'd ordered two pair.

Check Nashbar, REI, AeroTech and a few other discounters and you'll eventually see a pair at a price you'll like.