Revive Adserver is a free, open source ad serving system that enables publishers, ad networks and advertisers to:

Serve ads on websites, in apps, and in video players, and collect detailed statistics about impressions, clicks and conversions
Manage campaigns for multiple advertisers and from ad networks all at once, via an easy to use interface
Define rules for delivery of campaigns and ads, including frequency capping, URL targeting, geo-targeting
Track and report campaign performance, including click-through rates, conversion rates, revenue, eCPM and conversion details, like basket value and number of items purchased