You might try this excel implementation: http://rmtheis.wordpress.com/2010/02/16/microsoft-excel-implementation-of-the-needleman-wunsch-sequence-alignment-algorithm/

I haven't checked to see if that's DNA only or if it supports a custom substitution matrix and amino acid sequences as well, but it's at least something. For what it's worth, global alignment algorithms are actually pretty easy to write.

Something like http://ds9a.nl/nwunsch/ or this: https://github.com/aebruno/needleman-wunsch