Park it in BRK?
BRK has stated that they'll buy back in when prices are reasonable again, so it's an automatic "sell-high buy-low" strategy.
markets...irrational... longer than you stay solvent, etc.
I mean their cash pile is also invested in money markets (so you get that), and the rest of the portfolio consists of quality companies where their (combined) valuation didn't explode in the last 1,5 years. So it's an opportunity to invest into something that might not be overheated.