Nuffield Health (used to be Greens Gym, AKA the 'posh gym' in Norwich) are having an open weekend this weekend (10th and 11th). Free gym passes, fitness classes, use of swimming pool, jacuzzi, sauna. Give 'em a fake telephone number and you won't be pestered to join up afterwards.
Norwich Fitness & Wellbeing Centre
Barrack Street
Norwich
NR3 1TS
01603 857 321