Best April Fool's joke online we've seen? Google Nose:
The new scentsation in search. Coming to your senses: go beyond type, talk, and touch for a new notation of sensation. Your internet sommelier: expertly curated Knowledge Graphs pair images, descriptions, and aromas. Take a whiff: the Google Aromabase - 15M+ scentibytes. Don't ask, don't smell: For when you're wary of your query - SafeSearch included [editor: Ha!].
The mobile aroma indexing program is a hoot. Well played, Google. Video below.