Reference for integration Does anyone have a good reference for a book that already assumes knowledge of calculus/analysis and whose main focus is computing more difficult integrals? I'm looking for something which will have a lot of worked examples for differentiation under the integral, tricky substitutions, unusual contours, etc.
Most of what I've found in terms of references simply compile a long list of integrals, many of which are more tedious than insightful. My goal is to be able to get better at computing integrals that can be done by hand in a reasonable amount of time, but may require some ingenuity (like in math competitions, for example). So any discussion of heuristics and problem solving techniques in integration is a plus.

I've considered buying this book many times -
http://www.amazon.com/Irresistible-Integrals-Symbolics-Experiments-Evaluation/dp/0521796369
perhaps you will, and let me know how it is! 
Edit - although contour integrals are avoided, real methods only. Reading Ron's "best of" and using any good complex variables book (Ablowitz and Fokas recommended) should give plenty of practise at that. 
Actually the wikipedia page http://en.wikipedia.org/wiki/Methods_of_contour_integration has heaps of examples. 
