burn it off or add it on?

there's a 3 hrs spinning session this saturday. a great calorie burner for sure, but will i cope this 3 hrs thingy is another story. the 45 mins class was a torture for me at times, especially when it's endurance, strength, or interval instead of normal spinning. sometimes i acted serious like i was trying very hard when actually i kept on decreasing the resistance. whenever the trainer said "increase your resistance" i would increase a bit but when i found it tough i would then decreased it more than i increased it. there was once when i attended my fave instructor class and i was not in the mood to push myself that i used the normal resistance but pretended i was working hard. i remember him saying in between tracks "don't cheat yourself. i can see if you are working hard or not from the way you push your wheels. come on .. mind over body". he might not be addressing it to me but i was quite ashamed with myself that i added the resistance afterwards. it was actually a fun class - imagine you closing your eyes listening to the music picturing yourself doing it outside based on whatever the instructor was saying "you're nearing the finish line. pedal faster .. beat the person in front of you .. come on!! .. there's a hill in front, add resistance and push yourself .. you can see the finishing line" and all other motivational words. a great adrenalin pumping with all the sweat falling from your face and the feeling after the class is over is totally awesome. the problem is to push yourself to start. so should i go for this 3 hours ride? i suspect the 3 hrs spinning will be a mix of endurance, strength, interval *contemplating*. one thing for sure though - there's going to be a lot of bananas distributed amongst us during the class.
i need to make up my mind by tomorrow whether it's a 3 hours of spinning or fish head curry lunch in JB? i might end up with neither and spend the day at home watching TV