Recently I've been trying out an exchange sacrifice in my games to get a feel for when this is possible and when I really should hold on to the rook. I randomly came across Kramnik - Kasparov from Linares 1994 where Kramnik sacrificed an exchange for compensation that did not involve a structural component. I think the play is very instructive. This is one of the games I plan to study in depth when I get a chance. My initial impression is that the sacrifice was forced because White did not have a good square to place the Queen on when Black played ...Bf5. In any case this is the type of move that cannot be played in CCA tournaments in the bigger venues where there's a room for parents to set up shop with their IPads because kids will surely run off and check Rybka or Fritz's ideas more than occasionally. Kramnik - Kasparov Linares 1994
Here are some of my exchange sacrifice efforts:
Exchange sacrifice for the fianchettoed bishop
Sicilian Style Rxc3
There's more examples including situations where the sacrifice may not have been justified or only marginally so. I will update the post with some of these later on.