The Tate Britain celebrates British art from the Tudors to today. Its holdings include large collections of works from Joseph Mallord William Turner, John Constable and William Blake. Its sister museum, just down the Thames River, is the Tate Modern, the world's largest modern art museum. The former power station now houses works from artists like Picasso, Matisse, Mark Rothko and Andy Warhol, and even an impressive collection of contemporary art since the 1980s. Entry is always free, except for tickets to special exhibitions.
Theater lovers can take advantage of same-day discounts, often half the normal price by lining up at the official TKTS booths at Leicester Square and Brent Cross booths. These stall and dress circle seats can be the best tickets in the house to some of London's hottest plays, musicals, operas and dance performances.
During the summer take advantage of free outdoor events as well. Crutchley recommends hanging out on the South Bank of the Thames River by the National Theatre and Royal Festival Hall to get dates and tickets, as well as at the Scoop in More London, near Tower Bridge. For music concerts, check local listings in the Independent or Guardian.
"Come during the Proms to hear the top orchestras in the Albert Hall for 5 pounds a ticket. It's truly an experience," Crutchley says.
Add to your list: rotating exhibitions at the Serpentine Gallery in Hyde Park, tours and workshops at the Royal Opera House and the new Saatchi Gallery.
London can be a surprisingly kid-friendly town. The bigger exhibits will cost you, but its many beautiful public parks have playgrounds and sports facilities free of charge.
To capture the kids' imaginations, start at the Tower of London. One look at the old castle and crown jewels, and their royal fairy-tales will start to come to life. Be sure to stop at nearby London Bridge, as well as Kensington and Buckingham Palaces en route.
For some medieval gore head to the London Dungeons, which displays the gruesome methods of torture used in this former prison. It now also includes spooky rides with special effects.
Instead of the pricey Regent's Park Zoo head to the south side of the river to the Vauxhall City Farm. Entry is free Wednesday to Sunday, and kids will love getting to pet the animals, get lessons in pony grooming and picnicking on the lawn.
If you can drag them to a museum, the Science Museum offers interactive exhibits designed for kids. The Imperial War Museum will also grab their attention with life-size old planes and military machinery hanging throughout.
For a cheaper alternative to the classic British afternoon tea, skip Harrods' and head to the Original Maids of Honour in the Kew Royal Botanical Gardens. Enjoy its secret-recipe cakes outdoors or by a log fire in the colder months.