Some tools are so much fun they might as well be toys. Like a microscope or a telescope, an oscilloscope shows you parts of the world that you can't see any other way.
I love my Tectronix TDS 3032 oscilloscope.
300 Megahertz, 2.5 billion samples per second. Dual trace. It has a computer inside, so it can store the waveforms on the built-in floppy disk or the optional RS232 port in Excel format. It can be battery powered for field use. The display is in color.
And it's the size of a lunch box.