ThoughtWorks take the time to get to know their candidates and they encourage you to get to know them (some employers see recruiting as more of a one-way thing). This is the best interview experience I have had at any company to date.
Applied on website
Initial phone interview - about 30 minutes
Homework assignment - took me about 3 hours
Wonderlic aptitude test & non-technical coding logic test - about 2 hours
Interview day: group problem solving activity, presentation, cultural interview, consulting role-playing exercise, technical interview