Does the rule of three still work?

You need at least two to form a pattern, so you can't break your pattern with two; if you use more than three, you risk making it too long, and you don't want to bore your audience for a moment.

The rule arises from that, so it's only natural -- but in writing, rules are drawn from work; work is not written by rules.

In other words, it is a fine way to get laughs, since most people won't know it's going on, but whatever's funny is funny. I'm sure I could invent some rule-of-three lists that fail miserably.

I think you broke the rule of three in the example, since there were four things. I tried it both ways -- milk, eggs, grenades; milk, eggs, grenades and yogurt -- and I think the one with only three in it works better.

Basically, funny to one isn't always funny to another. And if it works, the reader isn't tired of it. If it doesn't, then the reader sees it as old hat. It's all in the delivery.