Yes Jungfraujoch is pretty (if that's how you spell it?) they're plenty of places to see, Gstaad is not too far off which is famous for being a destination for celebrities, it's not really too different from other towns in switzerland besides it's seasonal clubs and expensive shops. I would recommend Montreux if that's not too far, just under 2 hours away I would guess...you can see the lake geneva, I personally think it's the best place to be to see the lake. Montreux is a bit of a culture trip too because of Montreux Jazz Festival history! And if you want to stretch another 10 mins away from Montreux you can see the world's only official olympic museum in Lausanne. It's a shame you're not staying for another two weeks in Interlaken as Greenfield festival will be coming, a rock festival with big names from the usa, canada, uk etc Also transport is pretty direct, simple and very clean so the train system would be ideal to do all this travelling! Speaking of which, if you take the 'Golden Pass Train' you can see so much of switzerland from their 'panoramic windows'.
in case for the future … http://www.greenfieldfestival.ch/intro/index.php
have a great vacation!
live in switzerland, travel all over the place