As post #3 mentioned, the 'grandpa' one.
An older man I know, very intelligent, had six grandchildren. Three of them were traveling overseas, I've forgotten now but let's say Italy, and he was aware of their itinerary. He received a call from one of them who in a rather muffled voice said hi grandpa, this is John. I've got a cold, can you hear me OK? We are in X city, and I accidentally ran into a lady who was crossing the street. We're all in jail, they need $900 for bail, and we need to contact an attorney, they've taken our passports. A few more sentences, then John asked him not to tell anyone and gave him a number for the 'jail'. He called the number, 'they' verified the story, he then called the attorney and paid.
This from the FCC.
Grandparents often have a hard time saying no to their grandchildren, which is something scam artists know all too well.
Scammers who gain access to consumers' personal information by mining social media or purchasing data from cyber thieves can create storylines to prey on the fears of grandparents. The scammers call and impersonate a grandchild or another close relative in a crisis situation, asking for immediate financial assistance. Sometimes these callers spoof the caller ID to make an incoming call appear to be coming from a trusted source.
Often the imposter claims to have been in an accident or arrested. The scammer may ask the grandparent please dont let mom and dad know, and may hand the phone over to someone posing as a lawyer seeking immediate payment.
https://www.fcc.gov/consumers/scam-alert/grandparent-scams-get-more-sophisticated