Also related to time, the @ symbol ("atto" in Japanese) is often used instead of 後 or "ato" (after/in).

Examples:
＠15分　-- ato jyuu-go-hun (in 15 minutes)
リキャ＠４分 -- rikya ato yon-hun (recast in 4 minutes)
レイズ＠２分 -- reizu ato ni-hun (raise in 2 minutes)

Or other uses:
＠3人 -- ato san-nin ((full PT) after 3 people)
＠1回 -- ato ikkai ((after) 1 more time)


One more good symbol to know when talking about time is 半 or "han" meaning "half".

９時半 -- ku-ji han 9:30
1時半 -- ichi-ji han 1:30