This is such a cheap, effective way to workout. All you have to do is find some steps.. the more the merrier (or harder!). So it really is up to you how much of a workout you want.
All you have to do:
Run up the stairs as fast as you can, walk down and repeat x8-10.
Jump squat up the stairs, walk down and repeat x8.
Lunge kicks (front foot on the step and kick the other leg back, then step the leg you kicked back onto the next step), walk down and repeat x8.
Take extra rest when you need to.
Theres trampolining places popping up all over the place now. Some offer workout classes but, you could just go with friends and jump around for an hour. You will work up a sweat and won't even realise you're working out. Plus, it's a good excuse to get out of the gym and spend some time with your loved ones. It's estimated a 150lb person can burn around 400calories for an hour of jumping! It's a no-brainer.
Another social activity where you won't even realise you're actually 'exercising'. You can really feel it in those thighs afterwards. More of a winter activity but, put on those skates and skate 'til your hearts content.
Tennis (or Badminton/Squash)
Another sporty one that involves a bit of hand-eye coordination. You can do this alone or with friends. You could take lessons or just have a go. No doubt you'll be pro in no time ;) Again, put in your all, and burn some calories running around the court like a crazy person. Whack that ball and give those bingo wings a run for their money!
Please tell me i'm not the only one that loves a good Beyonce impersonation in the mirror. Bit awkward if i am. But, if you haven't tried it, put a music channel on the TV or Youtube, blast some Queen Bee or RiRi and get your dance moves on. Cue, 30mins of pretending to be Beyonce on tour and i guarantee you'll be a huge sweaty mess questioning your dance moves on a night out (you don't look so attractive without the beer-goggles). Alternatively, actually go to a dance class (i like Zumba) or use Just Dance on your neglected Wii console. I've tried this recently and believe me.. it WILL be a workout!