Ramifications of a hung parliament after UK election

What happens if the voters’ decision leaves no one party with a majority? Irish Times quotes from Peter Riddell's lobby briefing, “There is always a government, there is always a prime minister, bar the 20 minutes going up and down the Mall. It is legally necessary, for obvious reasons. The queen is not involved. Last time, she ostentatiously went to Windsor. I don’t know what she will do on this occasion.”