The Visualforce Page
<apex:page >
<apex:enhancedList type="Activity" height="600" />
</apex:page>
Save it.
IMPORTANT: Don’t forget to set the security permissions for the Visualforce page so that the appropriate user profiles can view the page. (click the Security link next to the new Page name). I think I’ve said this before…I ALWAYS forget to do this and don’t notice my omission until the first user (without admin security) tries the new feature and gets the big bad insufficient privileges error.
The Tab
Create a new Visualforce tab: Setup -> Create -> Tabs -> New (on the Visualforce Tab section)
Select your ActivityTab Visualforce page from the dropdown list and then give it a Label and Name. You’ll also need to give it a Tab Style (color and icon). Pick the icon that feels right for you.
Click Next
Now, set the security permissions for your tab…what user profiles see the tab (Default On =Show in the tab bar, Default Off = Show only when you click on the + in the tab bar, Tab Hidden = No Activity tab for you!)
Click Next again
Now you need to set which Applications should display your tab. I’ll leave that up to you since you know your apps more than I do.
Click Save.
….and that’s it. You should see your new tab in the tab bar (if you gave your profile permission to see it). Notice just how much that Enhanced List tag gives you…all the view customization functionality that a regular object tab offers.
Additional Notes
Have I mentioned before that the Salesforce community is awesome. @dschach has another great post on his website addressing the same issue and @geraldinegray pointed out that this type of tab is also available in the Force.com Labs Action Plans product on the AppExchange. Check out both!
Kevin Swiggum is an IT Consultant and owner of Radial Web Solutions in Madison, WI. As a Certified Force.com Developer and Registered Consulting Partner, Radial specializes in Salesforce.com implementation and custom development. You can find Kevin on 
It might be worth adding a paragraph about overriding a user’s customized tab sets (IIRC there may be two different places you sometimes have to check if the tab isn’t showing up)
I have this tab in my org, and I love it – except…. I really miss the little ‘X’ to mark a task complete that you get on the home page. I would love, love, love some smart code writing person like you to come up with a way to quickly change the due date, status, or priority of a list of tasks from a view like this. Cookies might be involved.
If you are at all familiar with GTD, I would love to do my weekly review from here.
The related twitter exchange yesterday regarding this post reminded me of an old request that I haven’t been able to chase down.
I’d like to display the contact phone number (assuming that the task is related to a contact) to be included as an available field in the list view. Any known ways or making this happen?