Don't you just hate trying to line up all the PVC pieces in a sink drain? Wouldn't it be so nice if there was just a little bit of flexibility someplace in the drain line? After all, we did finally elminate the rigid speedways to get those great flexible ones that don't collapse.
Well the company Canplas has finally done it. A "P" trap with a swivel joint! It will drop down about 10 degrees (not up, to avoid negative slopes) and still seal tightly. Actually it is very simple -- rather than a flat joint they built a ball joint. Available in Home Hardware stores across the US & Canada.