  Context. Gaia DR2 offers unparalleled precision on stars' parallaxes and
proper motions. This allows the prediction of microlensing events for which the
lens stars (and any planets they possess) are nearby and may be well studied
and characterised. Aims. We identify a number of potential microlensing events
that will occur before the year 2035.5, 20 years from the Gaia DR2 reference
epoch. Methods. We query Gaia DR2 for potential lenses within 100 pc, extract
parallaxes and proper motions of the lenses and background sources, and
identify potential lensing events. We estimate the lens masses from Priam
effective temperatures, and use these to calculate peak magnifications and the
size of the Einstein radii relative to the lens stars' habitable zones.
Results. We identify 7 future events with a probability > 10% of an alignment
within one Einstein radius. Of particular interest is DR2 5918299904067162240
(WISE J175839.20-583931.6), magnitude G = 14.9, which will lens a G = 13.9
background star in early 2030, with a median 23% net magnification. Other pairs
are typically fainter, hampering characterisation of the lens (if the lens is
faint) or the ability to accurately measure the magnification (if the source is
much fainter than the lens). Of timely interest is DR2 4116504399886241792
(2MASS J17392440-2327071), which will lens a background star in July 2020,
albeit with weak net magnification (0.03%). Median magnifications for the other
5 high-probability events range from 0.3% to 5.3%. The Einstein radii for these
lenses are 1-10 times the radius of the habitable zone, allowing these lensing
events to pick out cold planets around the ice line, and filling a gap between
transit and current microlensing detections of planets around very low-mass
stars. Conclusions. We provide a catalogue of the predicted events to aid
future characterisation efforts... [abridged]
