Football

quick thought and this is probably never going to happen, so is probably destined to happen, but if Arsenal get knocked out of the CL group stages and get parachuted into the EL knockout stages, what would be the odds on Spurs facing them?

Spurs have to come first or second yet but if they did, and Arsenal finished 3rd in their CL group then...

From: https://en.wikipedia.org/wiki/2015%E2%80%9316_UEFA_Europa_League

In the draw for the round of 32, the twelve group winners and the four third-placed teams from the Champions League group stage with the better group records are seeded, and the twelve group runners-up and the other four third-placed teams from the Champions League group stage are unseeded. The seeded teams are drawn against the unseeded teams, with the seeded teams hosting the second leg. Teams from the same group or the same association cannot be drawn against each other.
In the draw for the round of 16, the procedure will be confirmed prior to the draw.
In the draws for the quarter-finals onwards, there are no seedings, and teams from the same group or the same association can be drawn against each other.

So they can't play each other in the round of 32 or (by the looks of it) the round of 16, but they can definitely play against each other from the QF onwards.

If they're both there at the QF stage then there's a 1 in 7 chance that they'll play against each other and 1 in 3 for playing against each other in the Semis.

If they relax the rules for the round of 16 then it's a 1 in 15 chance they'll play against each other then.