international pixel-stained technopeasant day

April is not only for fools' errands by there is a host of other lesser known holidays throughout the month--including the above-mentioned observance (23, which seems unfortunately moribund) meant to promote the gratuitous sharing of science-fiction and quality literature in general to the public by professions and quite a foil to the observance of World Intellectual Property Day falling on the 26th.  The remainder of the month is filled-out with a spectrum of apposition and nuance, including two days dedicated to engendering autism awareness (2 or the nearest Sunday) and one Earth Day (22) and one Mother Earth Day (also 22), space-flight (12), vigils for Easter, an ancient Roman celebration of manly virility (falling on the first), days of remembrance, and a feast for Our Lady of Good Council (26) and a day devoted to combating parental alienation (25). What sort of uncelebrated things would you conceptualise with a devoted day and with what surety could you say it's not already out there in the æther?