One does not simply play with explosive things, if one values the structural integrity of his or her appendages. On the other hand, we seem to have no problem watching someone else mix potentially combustible liquids together -- in this case, Coke and propane -- so we can see the results.
So, first off, thanks "kreosan" for making this video. The sacrifice of your Coke for our entertainment is certainly not in vain.
As the (translated) YouTube description explains, kreosan added lighter fluid to a bottle of Coke, causing the combination to expand "in volume by more than 500 times". With only one place to go -- out the top -- it's possible to create a soft drink rocket.
Taking a look at kreosan's channel, it appears doing crazy things with flammable liquids is just another day at the office, though you sometimes have to replace "flammable liquids" with "microwaves", "mobile phones" and "soap".
It goes without saying, but don't try any of this at home. That's why we have the internet.