Every year there is the Mathematics Colloquium of Wales at Gregynog. This year it's from the 21st to the 23rd of May. The week before, my girlfriend (Zoë) and I will be running from Cardiff to Gregynog.
This is a 150 km trip and we plan to do it with all the equipment we need (water, change of clothes etc...) on our backs. We'll run around 40km in 2 stints per day (20 km each) staying in B&B's at night. We won't be trying to beat any records time wise which is why we're setting out on the 16th of May (which will give us 1 day slack if we need it).