The story centres around Timofey Pnin, a Russian emigre who teaches in an American university, but is told by an unnamed narrator. Pnin is a gently amusing and very likeable non-hero. He's physically inept (things break just because he touches them, like the washing machine he can't resist in the quote above), he speaks an odd version of American English and his life is a bit of a disaster. But he is warm to his friends, tries to fit into his new homeland's patterns and is oddly loveable. The book shares the story of how he ended up in America, snapshots of his life before and after and ends with another disaster.
Like a lot of Nabokov's books, the narrator is not to be trusted and towards the end of the book his bias begins to show. Throughout there are clues that after the final twist you'll piece together, Nabokov's trademark butterflies (he studied butterflies and even had one named after him, they turn up in almost all his books) and wry humour.
But it's not a novel. Even Nabokov admitted it wasn't:
`You seem to regret that the book is, as you put it, "not a novel". I do not know if it is or not... All I know is that Pnin is not a collection of sketches.'
(Nabokov's letter to his publishers, quoted in the Afterword to the 1997 Penguin edition)
It's an amazing book though if you like to be dazzled and enjoy word games. It's just 170 pages and it'd be perfect gateway to someone new to Nabokov, it has the style of his bigger works but is light enough to be a gentle way in for those not familiar with it. For a Nabokov fan it's a reminder of just why he's so remarkable a writer.