What about for someone that just wants to try it?
Light a fire and blow it out 5 minutes into shabbos...
Know the famous joke about the guy who wanted to become Jewish?
Sometime into the learning process he spent a Shabbos with his Rabbi, shortly before the end of Shabbos the Rabbi comes over to him and reminds him that he's not allowed to keep the entire shabbos so he needs to do a "Melacha" (action forbidden on Shabbos)
He replies "Oh, Don't worry - I already took care of that, I carried outside"
The rabbi responds "But there is an Eruv"
He says back "Ha, I don't hold of the Eruv"