I know the kind of pill you're talking about, it's just that I'm not sure at the moment what it's called. Hopefully another person here will know. By the way, 'long life pill' helps to expresses the point, but it's definitely not the best choice of words. The reason being, 'long life' refers to things like batteries, which are recharged after they've died out. That is, in order to be immortal, one need only take one pill. There's no recharging--taking more pills--required.
I'll see you in the Chinese New Year. (in the span of the year)
I'll see you at the Chinese New Year Festival. (at an event)
I'll see you on Chinese New Year's Day. (on a day)
- For Teachers