New version of Rx Contrib
Rx Contrib has new version (1.3)

Release Notes
- Bug Fix
- BufferWithTimeOrCount with flexible time period enabled
when ever the time period elapsed it will use the lamda for getting the next period
this feature is a join effort of Amir Shitrit and Bnaya Eshet
Code Snippet
- IObservable<long> obs = Observable.Interval(TimeSpan.FromMilliseconds(10));
- var bufferQueue = obs.BufferWithTimeOrCount(() => TimeSpan.FromMilliseconds(500), 10);
you can download the source or binaries from here.
you can install the Rx (the Rx framework is a prerequisite) from here.