A thingamajig; something the name of which is unknown or cannot be recalled.(noun)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "thingo" in a sentence
"I think I'll try your 'thingo' recipe one day soon and see what Jamie thinks."
"You can't even begin to imagine how many things I end up describing as a "thingo" or "dealy" a term I unabashedly stole from a Simpsons episode several years ago."
"Oh - and I think the way I wound up seeing it was neat; I ran into thingo, he invited me for tonight's show, I said I'd never heard of it, sounds great, then I discovered it was the night for the monthly Perl Mongers meeting."