Upsampling - but seriously folks

Any fans of upsampling out there? Anyone have experience with upsampling in which it actually makes your source sound better?

Personally I don't see how it can possible make any difference, but I'd like to hear from those of you who have had a positive experience.
The technology is always worth knowing and understanding but in this case I would just listen and compare.   Either way can be done well or not.   What any individual will prefer soundwise cannot be predicted.

FWIW I have both oversampling and non oversampling DACs in that the technology interests me to compare, and I find each sounds much different but very good in its own way.   Lots of good flavors of good quality sound out there.
mapman - Agreed - Knowing about the technology is fun and useful, as long as, in the end, you let your ears make the final decision.