timefilter
This script reads stdin and filters it thought to stdout based on the time. This enables a very noisy output to be sampled in small chunks.
An example of where this is useful - analysing the strace output of a long running process. Rather than storing the full strace output this script allows you to capture a few second long intervals at regular intervals.
The source code is being maintained on GitHub here: timefilter
I've set up an Ohloh tracker here: timefilter