Wasn't there one a couple of years ago that involved the Bruins, Sharks, and Habs?
EDIT: Found it...
23-Jan-03 Montreal Canadiens traded Jeff Hackett to the San Jose Sharks for Niklas Sundstrom and a 3rd round selection in 2004. Then, San Jose Sharks traded Jeff Hackett and Jeff Jillson to the Boston Bruins for Kyle McLaren and a 4th round selection in 2004.
...or does something have to go from the B's to the Habs to make that an official three-way?