If you're joining channels with IRSSI and keep getting spammed with all the IRC activity, just run the following in the prompt (for this example, I am in the #haskell channel):
/IGNORE #haskell JOINS PARTS QUITS TOPICS MODES
Don't forget to save your configuration (located at ~/.irssi/config) with
You won't see any IRC activity now and can focus on the important stuff!
For more advanced IGNORE tips, check Joost's blog about it
 :: http://joost.vunderink.net/blog/2010/09/02/irssi-tricks-ignores-and-hilights/