Best way to start desktop application development for a web developer

Question

I'm a web developer right now and I do that professionally. (PHP/MySQL/JavaScript) (Java/MySQL/Javascript) (RoR)

I make some scripts and sell them too.

Now I'd like to add desktop application development to my repertoire.

What languages/frameworks would suit me? I would ideally like to learn and get ready to code a few software and sell them.

You could possibly say Rapid Application Development(RAD) methodology suits me. So please suggest languages/frameworks that can complement RAD more easily.

Answer 1

Try out RealBasic it's really basic and it's RAD, Rapid Application Development platform

Also it's cross platform.