What are the various sporting activities we can do in Manali?

There are few sport activities in Manali itself,

Cycling/Biking : Motorbikes/Cycles are available on rent

River Crossing : In Old Manali there are couple of river crossing opportunities. For couple of hundred rupees you can do this. (that is what I am doing in the pic above)

Trekking : There is a Himalayan Trekking group in the main market which takes daily treks which you can join. They also customize the treks for a group if required. Other tourist guys will also take you trekking.

Apart from these adventures that are in Manali itself, there are a lot more activities to be done around Manali.

White Water Rafting : An hour or so from Manali are the Beas river rafting groups. You can go on 5/7/9 km rides. Its a lot of fun!

Paragliding/Skiing : At Solang Valley which is again just a few hours from Manali - you can do paragliding, skiing, ropeway ride, zorbing etc.. Its quite an adventure spot.

I am sure there are still more adventure sports like rock climbing that would be available in this region for a real adventure buff! If you go later in the year post May the higher altitude places like Rohtang/Chandrataal would be open. There would be lot of fun activities there as well :)

Also, you can select from various Manali tour packages available, as these packages often include adventurous activities as well.