To multi task, do you have to be able to chin-hold the phone in place while you eat lunch, puzzle over math problems, and peck out your book report?  Okay, well, yeah.  That's one way to look at it.  Truth is, you can multi task simply by being more efficient and better organized.  The key is to complete tasks sooner - not necessarily all at once.  Here are a few tips to stay on top of multiple jobs:

The bigger the juggle, the nastier the drop.
That's the risk.  Find a comfortable balance, and ask for help when it's appropriate.

Pull the plugs on disruptions.
Working harder is no substitute for working smarter. If the cell phone and ear buds aren't helping, they're hurting.

Pair up to pare down. 
Working big projects at the same time or back-to-back might be too draining.  Pair a big project with a smaller, simpler task.

Tools save time. 
Have a notebook handy to capture thoughts, lists, and notes; and investigate planning products that help budget time.
Know when to get crackin' and how to get creative managing your workload.  As the saying goes, "many hands make light work."  And it's okay to say "no" to extra activities every once in a while - save some time for you!