I went on a Backup multi activity course a few years ago. It was good fun and built my confidence. Some of the people I went with were more affected by it than I was; especially some of the tetras. Have some good memories like going clubbing (in Keswick!) midweek; 8 people being lifted up a huge flight of stairs. No disabled toilets so people doing sic's into the trough next to the drunken locals. The local girls flocked to the chairs as they were fed up with being leered at by drunken lads standing by the bar! Blokarting was great, wheelchair skills was very useful; I surprised myself. Camping was wet but fun. The view from the top of a large hill was breathtaking (as was the push up). The climbing wall was a waste of time.
I did a tandem freefall to help raise money for Backup (£500) and loved it to bits; it was amazing, but the scariest thing I have ever done was to try horse riding at an activity centre; the damned nag had hips like John Wayne; I hated it!
I find it difficult to get a week to do activities now (I work full-time) so I help out with Sportability in the South West UK, they do day events like quadbiking and sailing, but there are also possibilities coming up for more 'committed' activities as well. It's a national charity so there are things to do across the country. Check out the website:
www.sportability.org.uk