I still recall coming across the "Sams Teach Yourself Tcl/Tk in 24 Hours" book at my office. I had been doing Linux Samba administration at that time and some of the tooling was written in tcl. So I brought the book home. It was the first time I had ever doing any GUI stuff that wasn't Delphi/VB/FoxPro! I loved it! I quickly realized I had nothing interesting I needed to build at that moment... so I put it back down. But just realizing that GUI programming was in reach without all the heavy Win32/GDI or Winforms, was so cool.