At the risk of getting boring, I've just remembered another!
We were passing through the south of Uganda on our trek home, and the hour was getting late, almost dusk. We saw a level piece of land off to the side of the road, and pulled over onto it. The ground was very dry, with broken and dead stalks of grass, which pricked my sandal-clad feet. The few local cowherds around gave us an odd look as we arrived, and then wandered off. Ian got the little tent up, and then we had a meal, and played games with the kids until it was time for bed. We hadn't been in the tent all that long, when I was aware of something tickling my face, and then I felt another little tickle. I looked up, and there was a small stalactite of ants hanging off the apex of the tent. More were making their way along the ridge, after climbing the pole at the door end. They were deliberately targeting our heads!
We realised we must have pitched on an ant trail, and they weren't among the world's smallest! We vacated the tent as quickly as possible, and spent the rest of the night in the LR. The next morning, there wasn't an ant to be seen in the tent, but they were starting to climb the LR. Ant trails? the area was full of them! Makes me wonder what the prickles I felt on my feet were! We were out of there at the first opportunity!
Strangely, our next stopover, of about 3 days, this time with our bigger tent, saw us on top of a trail again, but all they did was occasionally march through the tent and out again.