For those looking for an enjoyable, not-too-difficult Sunday morning ride, consider joining in on the GDB "Sunday Roll"...  It departs from the northeast corner of Preston and Royal at 9:30AM (through March), and goes out to points unknown, for roughly 30 miles over the course of three hours.  Typical rolling pace about 16, no-drop with regrouping and one rest stop.  It's a very social ride, and guaranteed you will see parts of Dallas that you never knew existed, at one time or another.  (However, please be able to do flat cruising at a 15-16 pace..)
 
A word of caution, though -- if you show up on a 'bent, everyone will assume you'll be taking the lead up any difficult hill climb....   (just kidding)
 
We did an unusually heavy sightseeing-related tour today, due to having guest riders from out-of-town with us.  I took a BUNCH of photos, which you can see at:  
 
 http://www.greaterdallasbicyclists.com/gallery/DSSSR