Visiting relatives

[lnr]

My sister Steph is coming to visit me for a couple of weeks on Wednesday. Quite a long visit really. When she's in a good mood she's great fun, but I have reason to suspect she might be a bit fed up. She's coming to stay because she's flying back from Ukraine with her foot in plaster due to a torn ligament and my parents are away on holiday at just the wrong time and she probably can't cope on her own.
I'm wondering things like what sort of food to get in for her in advance, how to keep her amused, and so on. And silly things like do I reboot my computer into windows for her or create an account in its linux personality instead. She's emphatically not a geek and I fear our lifestyle may turn out somewhat boring for her. Wonder if she'll want to come along to the pub on Thursday.
Hopefully we'll have a nice time anyway. Any ideas for amusing not-very-mobile relatives in Cambridge?