Today go back to the project(s) you identified as "that which your boss cares most about you having completed".
First, figure out the status and next step for it/them.
Second, if the next step can be completed in less than 30 minutes, do it or identify what needs to happen before you can move it forward.
Third, email a status report to your boss. "Hi, I thought you'd be interested in an update on what's happening with these projects…" Make sure it covers current status, next step, any actions required by others to move it forward, and when you're expecting to be able to do that step or meet with the others to get it rolling. Be concise; bosses really like having a clear picture from a brief message.
Find all the open projects that are taking up more than a shoebox or a binder's space. Jot them down on paper. Mull them over a little.
Circle the ones that still matter to you.
Put a star by the ones that you'd also enjoy working on if you suddenly magically had a completely free day tomorrow.
Draw a dotted line through the ones that don't matter to you anymore.