I was going to mention using aluminized duct tape too, I've used it for several
projects, including lining plastic trays I keep parts in for projects. Kind of like
the pink nonstatic bags but more permanent.
Instead of MOVs, I think Transorb devices are better at handling ESD, and you can
get ones for protecting different voltage levels. These are actually like very low
inductance zener diodes. I don't think they wear out like MOVs. Can put them on
I/O lines that go to external switches, etc.
The other thing that helps, in conjunction with the clamping diodes built into
all CMOS microcontrollers, are small series Rs in the I/O lines. This helps limit
the current into the clamping diodes. For input lines, you can probably use 5-10K
ohms. For output lines, I use 220-330 ohms. I always use them anyways to
protect the lines from overvoltages and short circuits, not to mention ESD.