This is a socket-style table leg mount that fits a 2" ID/60mm OD PVC pipe. I did not add side screw holes because I wanted it to be easily dis-assembleable (so that I can use different heights of table legs).
If you found this useful, please share your work and be sure to peruse my other submissions which are almost as varied as they are many:
http://www.thingiverse.com/3E8/designs
Enjoy!
Nov 24th, 2015 update: If you have a lot of too-short-to-use 2" PVC pipes lying around, you can couple them together with this:
tablelegmount.stl | 182.3KB |