Yo-Yo
Bruce didn't know who gave Tony the yo-yo, and he didn't want to know, because looking into it further would cause additional aggravation. And when one was repressing the Hulk, aggravation should be avoided.
It wouldn't have mattered anyway, because Tony would still have the damn yo-yo, spinning it and playing with the string and sharing a long spiel about robotics and where his latest competition had gone irreparably wrong in their designs, while he had another screen up on youtube showing one trick after another done using a yo-yo. Which would inevitably lead to Tony's attempt to recreate the trick, and a hard piece of plastic connected to string clattering around or hitting the side of the billionaire genius' head, or flying across the space to knock Bruce's screen away again.
And then the bots would come whirring out from their charging stations, practically begging (as well as robots with no ability to speak could beg anyway) for some kind of mess to clean.