When the Cincinnati Bengals traded Caron Palmer to the Oakland Raiders, they received a 2012 first-round draft pick and a 2013 pick that is a first-rounder if the Raiders make the AFC championship in the next two years—if not, a second-rounder.
The conditional part takes a bit of risk out of the deal for both teams. If Palmer leads the Raiders deep into the playoffs, they pay more for him. If not, they don't.
The Golden State Warriors are currently exploring renting Dwight Howard from the Magic for one year in the hopes of re-signing him and making playoff runs with Howard protecting the rim and scoring like mad with Monta Ellis.
But what if the Warriors give up a first-rounder (and Steph Curry) for Howard only to see him leave after a year, and then no longer have a draft pick to help them rebuild?
Why not have the Warriors give the Magic a 2014 first-rounder only if they win 50 games in 2012-13? The Warriors are much more confident about going for Howard now, because they only give up assets if they don't need those assets as much.
How many more NBA trade rumors could we read about if they could do this? And hopefully teams would more efficiently move players, too.