It's interesting that you bring up poker. When I was doing my CV a few years ago I deliberated whether to state poker as I was in a few clubs, went to casinos regularly and of course played online. I thought better of it as it's gambling, but some people see it as willing to take calculated risks.
Well just stating that doesn't really tell anyone anything, just playing poker doesn't necessarily add much value A guy showing that he's made 200k in his final year of uni and that he's familiar with the theory is demonstrating something useful. He'll probably answer the quick mental arithmetic questions or basic EV calculations very rapidly. + If he's happy staring at 4+ online poker tables simultaneously then he can just as easily focus on multiple price ladders while trading.
I've not actually used spreadsheets much at all though I know basically how they work but I have extensive programming experience and used to work in database development so could get up to speed fairly quickly - but I'm also aware of how much I don't know in terms of data manipulation/handling techniques, etc. for spreadsheets.
You'll probably find that you'll be more competent at using them within a very short period of time than most of the people who use them every day.
Interesting. I've spoken to a few people who say that when they're reviewing CVs, it's the people that actually show a bit of character who appeal to them. It differentiates these CVs from the countless boring ones that just tell you how smart someone thinks they are.
Qualifying stuff can be useful, casually playing computer games is probably not worth mentioning, running/organising a team that plays in tournaments etc.. perhpas has some sponsorship or has won cash prizes etc.. is worth noting, not just to show that it's a serious hobby but also to demonstrate some additional skills/responsibility.
I think any sort of hobby or volunteer positon where you have some level of responsibility and take up your spare time to organise stuff is worth mentioning, whether it's gaming or running a 5-a-side football team or helping to lead your kid's cub scout group.
For general interests, I've always tended to leave a line or two at most though I think adding some detail or context is useful, like I had scuba diving listed at one point (I've taken it off now as it's been years), at one interview the guy who ended up hiring me mentioned it:
"Oh, you're a scuba diver too, BSAC or PADI?"
"BSAC, I trained through the scuba club at uni"
"Right answer
"
Now I doubt that was the deciding factor or anything but it did occur to me after that perhaps some people who've simply gone on holiday and tried it/bagged a basic PADI open water qualification might list the same thing under interests but simply trying it once or twice on holiday is rather different to being an active club member (elected to the committee in my final year, so actively organising stuff too) and taking a few qualifications, going on several trips, learning about boat handling (and spending time helping to fix/maintain them) etc..