I came across some unusual strings in some embedded SH2A code I'm analyzing....
11 53 54 00 53 55 4E 44 41 59 00 4F 46 00 2E 4F 56 45 4D 42 45 52
. S T . S U N D A Y . O F . . O V E M B E R
Which I realized is just "1st sunday of November" if you subtract 0x20 from each byte, effectively removing the control characters from ASCII. But they're still using a full 8 bits per character (not that subtracting the control characters is enough to drop a bit anyway) so I'm left wondering why they would do it and whether it's something homegrown or just obscure.