It's time once again for a report on the Shed at Glenwood's $3 slider night. This newbie, which turned up last week on Todd Richards' menu, may be the best slider ever. The filling is beef bone marrow with a parsley-radish salad. Slightly salty, slightly piquant, and a tiny bit bitter, the silky marrow and crisp salad didn't cure my cold from hell, but sure did make me happy for a while. If it's available, you have to try it.