Legoland Windsor

If you want a nice day trip from London, Legoland is a good option for both kids and adults.  It costs 48 pounds for adults but is part of the Merlin Annual Pass (see London Tips here).

Tip: Do avoid half terms and vacations. I went there on May 28, 2015.  Despite being a Thursday, it was so crowded and the queue was extremely looooong.

At the Big Shop near the Entrance

Website: http://www.legoland.co.uk/
Address: Winkfield Road, Windsor, Berkshire, SL4 4AY
Transportation:
Option 1:

• Nearest Train: Windsor (may cost around 10-20 Pounds return per person) and then take a bus 191, 200, 600 for 5 Pounds return.  Might be good to get a single bus trip since you will just want to catch whatever bus back to Windsor.
• Windsor is a 30-40 minute train from Paddington with a possible change in Slough
• By Coach
• http://www.legoland.co.uk/Plan/Directions/By-Coach/
• Victoria Station by Greenline bus which includes the admission tickets (here)

Star Wars

This is near the Entrance and I am sure this is well-loved by all.

At the Star Wars Store

Model Factory Shop

Miniland

A nice area where you can find "Mini-versions" of various tourist attractions from Eiffer Tower in Paris to Tower Bridge and Buckingham Palace of London.

And they have Taylor Swift's Frame in Legos!

Holland

Sacre Couer

Louvre and Eiffel Tower

Buckingham Palace

Wembley Stadium

Brighton

St. Paul's

Big Ben and London Eye

London 

Horse Guards

Heartlake City

This is currently the place where LegoFriends have their show times.  They also do the Pirate shows here (nice stunts for kids).

 

Duplo City

This is more like a FUN water show place and Kids would love this.

Knight's Kingdom

This is more like a FUN water show place and Kids would love this.

Viking Land

Lego City

The Hotel

The Urinals :P

Others