staying in generator hostel for the first time. tips? local sights?

Biggest name attractions are the British Museum and British Library. The British Library has a permanent free exhibition of "treasures" and a current paid exhibition on UK and UK-creator comics, if that interests you.

A less well-known specialist attraction is the Wellcome Institute on Euston Road, which has a permanent exhibition on medical history and sometimes interesting temporary exhibitions.

If you're interested in British real ale, there's now the Euston Tap in one of the Victorian lodges outside Euston station. There's also a Cider Tap for traditional British alcoholic cider in the other one.

There are some excellent cheap Indian restaurants in Drummond Street, which is north of Euston Road near Euston Square underground station. Generally there are some hipster bars in the area thanks to the presence of University College, the new University of the Arts behind Kings Cross station, and the group of creative/media businesses in the Fitzrovia area west of Goodge Street tube station.

Use Google maps is the first tip. The second is to discover how easy it is to use the tube and busses to get around the city. The third is find a used copy of Rick's London guidebook, or find it online and read it. Very insightful info for a first timer. Might also read answers to the posts on the Helpline to learn more about the city you are visiting. Lastly, understand that London is an expensive city so budget accordingly for your June/July stay.

Looks like a nice hostel. They seem to rent towels, so you don't have to bring your own. There may be party going on there, but London has so much else to offer that I wouldn't hang around the hostel.