ACTIVITY TAB:

ACTIVITY TAB:
How to make tasks and events as tab ,it is simple to achieve by enhancedlist and custom visualforce tab.The code looks like this

<apex:page > <apex:enhancedList type="Activity" height="600" />
</apex:page>

Also you can use multiple list views in the same page instead of going to different tabs like this

<apex:page >
<apex:enhancedList type="Account" height="250" />
<apex:enhancedList type="Contact" height="250" />
<apex:enhancedList type="Opportunity" height="250" />
</apex:page>