If you got an extension to file your 2008 tax return and haven't done so yet, today is your deadline.
Details on this must-do tax task, as well as on other important due-date duties, can be found in Oct. 15 tax deadlines looming.
You have until midnight tonight to e-file. Or if you prefer paper, get your material to the post office so that it gets today's postmark. If you are using snail mail, I suggest you send your return certified so that you have a receipt noting the date.
And do't forget about your state tax obligations! If you also got an extension to complete those forms, it's likely that today is your final filing chance for those forms.