Summary

I made this for a project my brother has, rerouting roof runoff to a rain barrel. First print (photo) was too thin; the .stl I posted has a thicker wall (3mm). It should do nicely. Added 2 photos of the final. Note filament separation on the first, thin-walled, print.

Instructions

I have also included the bits-n-pieces I used to make this, along with some preliminary versions, in a 123D file, so you can remix to heart's content. Note, there is a copy of the 2"-I.D. (Inner Diameter) ring for coupling, and the two circles I used, with the "sweep" function to create the curved part, so you can make your own arbitrary joiner angles.
Step 1: Measure! The 2-inch I.D. pipe had about a 2.05 inch I.D, and a 2.383 inch O.D.
Step 2: Make a two-point arc with an appropriate radius (I went corner-to-corner on a 25mm square, so that's about 35mm radius) and sweep to the desired angle.
Step 3: Sweep with the large circle (the outer diameter of the joiner, about 3mm larger than the inner diameter).
Step 4: Sweep with the smaller circle on the same arc, which should carve the inside of the first.
Step 5: Snap the bend to the thick rim of one collar, snap the thick rim of another collar to the opposite end of the bend.
Step 6: Combine the shapes, save, and export the .stl.
Print it solid. I used 5 shells in Makerware.

2 inch PVC pipe joiner 33 degrees