Depending on the data, you can either use one of the following.
Google Spreeshet / Charts: I use this for real time analytics generated from our system to quickly visualize the information. There's a simple JSON API that lets you pull that in although their is limits on the amount of rows you can use.
Geckoboard: They provide dashboard type widgets you can configure to show you real time trends and information.
Highcharts.com: Simple chart generator. We use this in our Admin Dashboard to visualize all our data include cohorts and weekly KPI's.
I like simple and free.
