Jazz receive: Rajon Rondo, Kevin Garnett
Celtics receive: Al Jefferson, Kyle Lowry
Raptors receive: Randy Foye, Jamaal Tinsley, Jazz 1st round pick 2013 (and probably 1 more pick for them to actually do this - maybe a 2014 pick?)
Why the Celtics do it: Rumors have been flying for over a year now that the team wants to trade Rondo. They do that and get younger with Jefferson replacing Garnett.
Why the Jazz do it: They get a great point guard in Rondo and a veteran who plays great defense in Garnett. I may not like the guy, but he's still got game.
Why the Raptors do it: During Lowry's injury, Jose Calderon has been playing great basketball. When Lowry gets back, they'll have two starting-caliber point guards making almost $16 million combined. Getting an extra first round draft pick this year might be enough for them to part way. (Tinsley and Foye could also be replaced with Mo Williams, but with his injury he has almost no value this season. Other players that work salary-wise, and that the Raptors may be interested in: Paul Millsap, Marvin Williams)
If the Celtics have changed their tune with Rondo (or if they never wanted to trade him in the first place), then there's no way they do this. If Garnett decides he doesn't want to be traded, he can veto any trade, so there's that as well.
The Jazz may not want to trade Jefferson and/or Millsap during the season, and instead wait until the offseason to make a move. Taking on Rondo and Garnet also takes up most of their cap space for next offseason - although they'll have Kanter, Favors, Garnett, Evans, Hayward, Burks, and Rondo (plus Marvin Williams, if he opts in) on the books already; that's already a pretty solid roster. Re-sign Damare Carroll, bring in 2 or 3 role players and you're good.
The Raptors may be more interested in keeping Lowry and trading the older, more expensive Calderon. If that's the case, then there's little chance of them agreeing to this, unless we throw in at least two first-round picks (which I'd be OK with in this trade scenario).