If you’re not familiar with the 555 ... 5 MHz astable frequency for either part, which at least on paper, is faster than the LMC555. Looking Microchip’s reduced-functionality timer offerings ...

Here’s an interesting implementation of a classic: the 555 timer as astable multivibrator for the noble purpose of making weird music. [pratchel] calls this a Morgenflöte or morning flute ...