Other people have already said Ulysses and Mrs Dalloway, both modernist classics that take place in a single day. There are a couple of other examples of similar novels, but the only one that springs to mind right now is a deeply annoying experimental 'novel' called Fidget by Oliver Goldsmith, which I don't recommend at all. He wore a tape recorder and spoke out loud describing everything he did that day, then transcribed it all and that's the book. If you do decide to read it, don't say I didn't warn you.

I don't know if this will count for you, but there's a hypertext novel called 253 by Geoff Ryman which IIRC takes place over just a couple of minutes, with very short chapters describing the thoughts of each of the 253 passengers on board a train. He did later also publish a print version.