If you have an Airdyne Bike give todays intervals a try:
8x.5 mi recover back to under 120 BPM if you have a heartrate monitor. If not, take 2 minutes rest.
Over level 8 will give you a time of 1:20 on the big fan about 1:20 on the small fan. Try to get them all in 1:20 or 1:10