I was looking around the Sam and Max forums and I could only find separate threads for individual easer eggs. Think we could form a compendium of them?
I found this one I couldn't find a thread for:
On the bulletin board in the office, you see a paper bag max head.
This is a reference to the cartoon series sketch "Artsy Craftsy bit of Time Wasting Nonsense" that can be seen here:
Doubt I'm first to notice it though =P