Moods & Occasions Section - The Party Desk:

Spank Rocks YoYoYoYoYo, although rather offensive, is a definite banger. Their fabriclive cd is a bit more universal, and probably better for a wider audience. DJ Yodas fabriclive is also great.

That link between indie and electro for me is found in LCD Soundsystem. Try Yeah (Crass version) somewhere later in the evening.

Also, if you can find it, an compilation called Soundway Records Presents Cartagena! is great for outdoor parties. Sun is required though.