What have you done with UDAs?

[Vladimir Panteleev via Digitalmars-d]

On Monday, 22 June 2015 at 19:36:59 UTC, Kapps wrote:
> On Monday, 22 June 2015 at 19:09:40 UTC, weaselcat wrote:
>> I never seem to use them for anything, has anyone else done 
>> anything interesting with them?
>
> Like several others, I use them for generating command line 
> interfaces to set variables / invoke methods using reflection.

Same here:

http://blog.thecybershadow.net/2014/08/05/ae-utils-funopt/