I've had a few supervisors at the current place I work at who are pretty lax about slacking off- as long as:
a) the work gets done
b) it's not *too* invasive
for example, on super slow days (holidays, primarily, where I was required to be there for break/fix, but since things were running well I ended up having very little to actually *do*) I'd have my personal laptop in and was playing movies, offline games, or using the company's guest wireless to play minecraft or some such.
And yeah, I could *probably* write off El Reg as "technical research", but meh. (as I type, I'm waiting for an content index rebuild on a pair of DAG nodes, and keeping a weather eye on the backup job that's running, and waiting for a vendor to ping me.