several small C++, Lua, Ruby, OCaml things, with source code
FPDissect floating-point format viewer
||easily compilable C-90 source code (7 KiB)
Displays the structure of IEEE-754 floating point single (binary32) and double (binary64) precision numbers. (Requires 64-bit ints.)
GITI is a electric guitar music notation text format.
UTF-8 filter tool / library
Reads stdin and checks, filters, or replaces it as UTF-8 content. (According to RFC-3629 and Unicode 7.0.).
TXON format / library / tool
TXON minimal data format enables embedding structured data into text readably and unobtrusively.
‘Software Engineering Symbol’ generator tool
||executable Lua 5.1/5.2 source code (5 KiB)
||executable OCaml 4.00 source code (4 KiB)
Read the original article for explanation.
PPM image comparator tool
Minimal basic object system for Scheme R5RS
There are plenty of others, but all rather sophisticated and fully featured. This one is very small and simple.
CodeGauge C++/Java/C# lines of code counter Windows gadget
TimeGauge stopwatch Windows gadget
DeXhtml XHTML remover Windows tool
RubyGauge Ruby lines of code counter tool