Thought you'd NEVER ask!
It was the first appearance of what we call The Drip, a long time ago. It has been described here before.
My family (ex, kids and I) were moving house. Then-teenage Son and I were at the new place which was still virtually empty, trying to get the somewhat eccentric central heating system working. We'd set it going and it'd run for a bit and then fizzle out. Great fun!
So at some point after trying everything we could think of we were standing in the kitchen, probably discussing buying pickaxe handles to physically beat the boiler back into proper functioning, when
something emerged from the ceiling in front of us.
It was a big glob, looking exactly like wallpaper paste, which swelled downwards in size and then suddenly dropped to the floor with a loud SPLAT.
The glob then immediately disappeared. It didn't soak into the floor; it splattered everywhere like a huge pale jelly and vanished.
This all took a few seconds. Son and I only had time to gawp and point.
We assumed the boiler had overflowed and flooded the bathroom, even though the ceiling was dry, and so was the floor.
We rushed upstairs and checked the plumbing - no leaks. Everything in order.
There was a lot of 'What was THAT?' and 'Did you SEE it?' and so on. We had both seen and heard exactly the same thing, and had felt the floor and ceiling to find them dry.
It rattled Son so much that after a while he refused to talk about it any more, saying that we must've imagined it and somehow worked it up into a real memory!
The Drip/Glob was often experienced in the house after that, along with the Ghost Cat, the Inexplicable Warm Spot, the Night Footsteps and the rest. It's all on'ere somewhere.