How to do cardio while having an ankle fractured....?

about 2 weeks ago I was playing volleyball and I got my right ankle fractured in the game, I was giving to use crutches for an estimated time of 6 to 8 weeks and I was about to be on 2 month vacation and I was going to do cardio and plyometric excises but I can't duo to my fractured ankle. I was just wondering if anyone would recommend anything to do cardio because don't wanna gain weight, I'm not obese but I still have some belly fat that I wanna cut down AND also take care of myself in this time that I will be crippled..