mod_ePerl uses <? and !> by default, but they can be changed to whatever your fancy gets struck by: <perl> and </perl> <perl code=" and "> and so on.
there's also "wml" which does a nine-pass run over a source file to produce results, typically html... it uses some constructs like <: :> if you've inhereted some files from another distribution or installation or platform, they may have had such a beast or two installed that you don't. if you don't have them available you can get them: apt-get install wml apt-get install eperl and then man eperl man wml # and wml_tutorial but not necessarily in that order. :)