lots of choices!!
Ciao Bigcubfan!
Good for you, to combine a race while on vacation! I found lots of options in Tuscany although no full marathons. Two half marathons though!
I found there is going to be a race on April 15 right in Arezzo called the
Corsa del Saracino.
The website is not yet updated but it will continue to be a 13km race.
April 15 seems to be quite popular date, there is a series of
Vivicittà races across Italy and maybe beyond, all of 12km, to be held that day. In Tuscany, there will be races in Livorno, Siena, Viareggio and Florence.
Livorno Vivicittà
9.30 am - 12k
Uisp Livorno
0586-887433
livorno@uisp.it
Vivicittà 2011 - not updated yet for 2012
Siena Vivicittà
10.30 am - 12k
Uisp Siena
0577-271567
http://www.uispsiena.it - not updated yet
Viareggio Vivicittà
10.30 am - 12k
Uisp Viareggio
0584-963696
info@versiliasport.com
VERSILIA SPORT A.S.D. - the site is not updated yet
Florence Vivicittà Half Marathon
Piazza Santa Croce
9.30 am - both a 10k and the half (21,1km)
http://www.mediauisp.it/ (info still relates to 2011 edition)
The closest of these to Arezzo is the one in
Siena. Just so you know, the one in Siena is also the only one not marked as "competitive" which means it should be open to everyone in good health.
All competitive races in Italy (including the 13km in Arezzo) require that you present a certificate from your doctor saying you are in good health to compete in these races (I guess so that you take responsibility if you keel over along the way, it is your fault for overestimating your capabilities

) and others require that you be registered with a running club or association in order to participate (insurance purposes). I believe this is because so many of the races I've seen here are tied to some sort of athlete competition calendar and much less to a charity as is more common in the US and UK. In any case, usually foreigners just need a doctor's certificate which says you are fit enough to compete in a race (see
this form example given for the Florence Marathon)
Other races I found for your dates:
two on
April 9:
Prato Half Marathon (
www.maratonina.prato.it/) and in Massarosa (Lucca), the
40° Corri Massarosa - 18km - for info: G.S. Amici della Marcia Atletica Massarosa 0584/975809 (didn't find info on their site about it)
April 22 - Prato -
15° "Un Pò 'n Poggio"
Various distances, non competitive: 6k, 11k, 17k, 23k and 31k
Starts are "free", as long as you leave between 8 and 9am in Piazza Mercatale, Prato
Open to all, no need to have doctor's certificate - individuals can register on the same day up to 9am
http://www.gruppopodisticocrocedoroprato.it/
Bookmark these pages if you want to check back for others, I am sure some more "fun" runs are not yet listed so might be listed later on -
Toscana - Tutto Podismo and
Calendario Podismo (you have to enter "Toscana" at the top in the "Regione" search to filter the ones for the region).
Hope this information is useful as you plan your vacation! I recently ran my first half in Livorno and it was a great experience

We are sure you'll have fun!