At the RCOMM, we had a challenge in which data miners had to design RapidMiner processes solving unusual tasks. The three tasks were to design a process that creates the lyrics of "99 bottles of beer", apply a model on a data set of which a complete column was lost, and to create a process that computes the Fibonacci numbers. All winning solutions, challenge descriptions, and necessary data preparation processes are now on myExperiment:

http://www.myexperiment.org/search?query=rcomm&type=all

I think they are worth looking at since they apply quite some clever tricks.

Furthermore, we have seen a lot of interesting and brand-new RapidMiner Extensions at the conference. One of them, made by the DFKI, assists the data miner in choosing an appropriate learner for their data set and saves you from trying a lot of different learners manually. The extensions is available from our update server and is described here:

 http://madm.dfki.de/rapidminer/wizard

Try it out!