Great Cow BASIC (abbreviated as GCB or GCBasic) is an open source compiler that allows you to program PIC (Microchip) and AVR (Atmel/Microchip, including the ATMega328P in the Arduino Uno) ...

The new Flowcode 8 offers considerably more features that just scream to be tried out. Especially the addition of the new programming modes and working with C code and flowcharts is very impressive.