What to do at Interlaken

When your train down from the Jungfraujoch stops at Kleine Scheidegg, walk the easy marked path along the ridge to Männlichen---about a hour. There you can ride inn6-person gondolas down to Grindelwald. Then take the Pfingstegg cablecar up to the summer luge ( Rodelbahn).

http://www.pfingstegg.ch/index.php/en/

If you prefer n to do the walk on the ridge top, you can take the train from Kleine Scheidegg down to Grindelwald instead of the gondola---but the little gondolas are more fun.

From Grindelwald you can return to Interlaken directly without going back up and over the Männlichen ridge.

Just what I was going to recommend, but Lola beat me to it.

Why waste your time in Interlaken. The things you want to see and do and visit are in the Swiss Alps - which Interlaken is NOT. Skip Interlaken and at least go as far as Lauterbrunnen (20 minute train from Interlaken) and get a hotel there. Better yet, stay high up in Wengen or Murren (both car-free villages) they are both absolutely stunning.

Couldn't get hotels in lauterbrunnen and ended up booking in interlaken. I could travel to wengen or murren while coming back from jungfrau. But I would like to know where I should find the start place of those activities. Not much interested in taking cable car which we already cover in the previous day lucern to mt titlis trip.

WHat do you mean "start" the activities? You just get on a train and go. Logical place would be to start at a train station...like Interlaken Ost or Interlaken Est since Interlaken seems to be the location of your hotel.

I meant , where can I find the paragliding or zip liner, or chair lifting etc?

Why not check with your hotel for recommendations?

where can I find the paragliding or zip liner, or chair lifting etc?

Go to the Tourist Information office at the Metropole Hotel. They can make arrangements for paraglidingand give you info on other activites. The operators will typically pick you up in Interlaken and transport you to the launch sites via van. The landing area is at the park across the street from the Metropole so alternatively you can talk to a rep from one of the paragliding firms during the evening landings.

Not much interested in taking cable car which we already cover in the previous day lucern to mt titlis trip.

The cable car is not the attraction, it is the transportation. That's the case if you are heading up Mt Titlis or around the Lauterbrunnen Valley. Horizontal transportation is the train, vertical is the cable car, cog railway or funicular, depending on how steep the ascent is.

Cable cars are also called gondolas depending on size. Chair lifts are individual open-air mini-cable cars really and there are very few outside the skiing season when they convey skiers up the mountain so they can ski back down. They are the second most primitive type of transportation, with rope-tows being the simplest.

In the summer I can think of one at Kandersteg which takes quite a long time to reach by train as it is on the opposite side of the mountain range - very close as the (high altitude) crow flies but nearly two hours by train as you have to go all the way around. That one gives the altitude for a sommerrodelbahn - a summer toboggan on rails.

There is also - at least used to be - a chairlift out of Grindelwald.

I hope that you don't think that because you have ridden one train that you have seen everywhere they go....