Adobe Illustrator, using pen tool and mouse. No filters, meshes,plug-in's, brushes or nonsense, just the basics and some creative thinking and problem-solving.
It all starts with a sketch, which I find that nearly all present-day "graphic designers" cannot accomplish. Remember when creative studies had this whole "life drawing" requirement? I mean really... The pencil and paper technique is a dying art, and that's a shame.
Anyway, here's the thing I made. Definitely not my speed, but nothing says "fun, wow" or "we respect you as a creative" like being asked to draw things in someone else's style. Hooray and whatnot.